Such an apparatus of the type described in the preamble is often used for closing off openings, for example window openings, to which end the slats are disposed regularly over the surface of the opening and brought into a more or less overlapping position by being rotated about a vertical axis. The disposing movement and the rotating movement can be performed independently of one another.
The slats are automatically disposed over the surface of the opening by placing one carrier at an interval from another carrier, this interval being determined by a stop on the spacer strip. As the carrier moves further each following carrier is taken along with it, this movement again being defined by the following spacer strip. The drawback to the known apparatus is that the track in which the carriers are guided is relatively high, which does not improve the appearance of the whole curtain. The series of spacer strips stacked onto each other in any case requires a particular thickness, the dimension of which is added to the height of the carrier.